1. Field of the Invention
The present invention relates to a feed roller suitable for use in feeding a sheet-like object in a clamped manner.
2. Description of the Related Art
In general, feeder arrangements of the type employing rollers are utilized in various fields which necessitate the feeding of sheet-like objects. For instance, in the field of photographic development, such a feeder arrangement is incorporated in automatic development machines as a means of causing a long photographic film to pass through a series of processing baths.
In this case, the surface of the film that comes into contact with rollers, in particular, the emulsion bearing surface of the film that is exposed to development, requires careful handling because of its sensitivity. For this reason, it has been common practice to attach a protective material such as MOLTEN (tradename) to the periphery of each roller in order to protect the emulsion bearing surface of the film.
Such a protective material, however, involves the following problems. Attachment of the protective material to the body of each roller is time-consuming and, in addition, provision of the protective material amounts to a significant expense. When the film is to be fed while being nipped between pairs of rollers, the gap between the rollers is preferably made as narrow as possible in order to allow the film to be nipped therebetween. On the other hand, from the viewpoint of protection of the emulsion bearing surfaces, the gap between the rollers is preferably made wide so as to reduce the level of clamping reaction force applied to these surfaces. Accordingly, in order to suitably maintain the clamping force applied to the film, it has been necessary to adjust the sizes of the respective gaps between opposing rollers.